Signage is common for basic communications and is the most popular form of advertising worldwide. Advertising signage, for example, is extremely effective in the form of illuminated point of purchase signs, commonly found in airport terminals, bus and train stations, sporting arenas or stadiums, convention centers, hotels, and other public walkways, or places of high pedestrian traffic. These signs are decorative multicolored arrays and are retained in outwardly protruding illuminated cabinets or light boxes, the cabinets mounted on a wall, or other stable support structure, for example, a balcony front at a sporting arena or stadium.
Two exemplary signs 20, 20' of overall length (L, L') and overall depth (D, D') are mounted on walls 21, as illustrated in FIGS. 1, 2a, 2b, 3 and 4a-4b. These drawing figures are diagrammatic, to illustrate the structures detailed below, and accordingly are not to scale. Both of these signs 20, 20' include cabinets 22 (also known as a light box), of sheet metal or the like, with bodies 24, having rear 25, side 26a, 26b, upper 27 and lower 28 walls, an open front (side).
The bodies 24 of both signs 20, 20' may also include borders 29 (continuous or non-continuous along the periphery of the open side of the cabinet body 24), affixed to the cabinet walls 26a, 26b, 27, 28 by conventional mechanisms, to assist in preventing the graphic unit 32 from moving (or being pushed into) the cabinet 22. The borders 29 preferably have their outermost surfaces flush with the edges of the side 26a, 26b, upper 27 and lower 28 walls at the open side of the cabinet body 24, and may include an indented section (not shown), typically referred to as a screw trough, for receiving screws 35, rivets or the like.
The cabinets 22 enclose lights, for example, 800 milliamp (ma) fluorescent tubes 30 (also referred to as fluorescent lamps), of lengths ranging from eighteen inches to ten feet (46 cm to 304 cm), and diameters typically approximately 1.5 inches (3.81 cm), or other suitable illuminating devices. In both signs 20, 20', the fluorescent tube arrangement(s) are exemplary, and additional similar arrangements within these cabinets 22 are permissible if desired.
A graphic unit 32 is positioned in a retainer 34 (frame). This retainer 34 holds the graphic unit 32 in place against the cabinet body 24, as the graphic unit 32 abuts the edges of the side 26a, 26b, upper 27 and lower 28 walls and the borders 29. The retainer 34 is made of individual members 34a, preferably four (one for each cabinet periphery side), each member having lips 34b that abut the edges of the side 26a, 26b, upper 27 and lower 28 walls when the signs 20, 20' are properly formed. Each of the members 34a that form the retainer 34 attach to the cabinet body 24 by clamping screws 35, conventional threaded screws received in openings in the cabinet body 24, latches, hinges, or other similar attachments. When any retainer member 34a is removed from the cabinet body 24, the graphic unit 32 can be removed by being slid therefrom. Other conventional retainers for the graphic unit 32, such as friction fitting members, are also permissible.
The graphic unit 32, typically includes a graphic 36 (typically a transparency), sandwiched between a diffuser panel 38 (typically a translucent polymeric or plastic sheet), oriented rearward toward the cabinet rear wall 25, and a protective cover member 40 (typically a transparent or clear polymeric material), held in contact by the sandwich arrangement. The cabinet 22 of each sign 20, 20' has an internal length (l), from the innermost surface of the sidewall 26a to the innermost surface of the opposite sidewall 26b, and an internal depth (d), from the rear wall 25 to diffuser panel 38 (alternately expressed as the distance from the rear wall 25 to the plane formed by the edges of the side 26a, 26b, upper 27 and lower 28 walls along the open side of the cabinet body 24).
As shown by the sign 20, where the internal cabinet lenght (l) is ten feet (304 cm) or less, a single fluorescent tube 30, or tubes, depending on the sign height, span or spans, the entire internal cabinet lenght (l). Each fluorescent tube 30 is received in electrical connection and in a coaxial alignment with the respective sockets 42a, 42b (the center point of the socket substantially aligned with the center point of the fluorescent tube). For example, these sockets 42a, 42b, may be KULKA brand lamp sockets Cat. No. 582, 660 W-600 V/1000 V, available from Voltarc Technologies, Inc., 400 Captain Neville Drive, Waterbury, Conn. 06705, USA. The sockets 42a, 42b are mounted on oppositely disposed sidewalls 26a, 26b of the cabinet 22. These sidewalls 26a, 26b, may be of variable thickness to define wireways or raceways, that accommodate electrical hardware (wiring) for the sockets 42a, 42b (and in the second sign 20' as well). At least one of the sockets, shown here as socket 42a mounted on sidewall 26a, is spring loaded (depressably mounted) by a spring mechanism 43, to allow for easy fluorescent tube 30 removal, by depressing the spring loaded socket 42a.
The second sign 20', where the internal cabinet length (l') is greater than ten feet, requires the lights (fluorescent tubes 30) to overlap, as conventional off-the-shelf fluorescent tubes are not greater than ten feet in length. Each fluorescent tube 30 extends from sockets 42a, 42b, mounted on oppositely disposed sidewalls 26a, 26b, both sockets 42a, 42b, are also preferably spring loaded (depressably mounted) by spring mechanisms 43, for easy fluorescent tube 30 removal, by depressing the spring loaded sockets 42a, 42b. The opposite end of each fluorescent tube 30 is received in an adapter socket 44 mounted to a wireway 45 or raceway along the rear wall 25 of the cabinet 22. These adapter sockets 44 may be a "tombstone " sockets, shown in FIG. 4c (with its fluorescent tube electrical connecting mechanism 46 shown), such as a KULKA brand lamp socket, Cat. No. 530, 660 W, 600-1000 V, available from Voltarc Technologies, Inc., 400 Captain Neville Drive, Waterbury, Conn. 06705, USA.
The arrangement of the fluorescent tubes 30 (lights) in the cabinets 22 of the signs 20, 20', determines the internal cabinet depths (d, d'), that serve to establish the overall sign depth (D, D'). The internal cabinet depths (d, d') are less than the overall sign depths (D, D'), as this overall depth accounts for the thickness of the cabinet rear wall 25, any retainer portion that does not overlap with the cabinet body 24 (the non-overlapping portions of the retainer 34 including the graphic unit 32). These internal depths, "d" for sign 20 and "d'" for sign 20', are a combination of two distances, "d.sub.1 ", the cabinet rear wall to socket center/fluorescent tube (light) center distance for the first sign 20 and "d.sub.1 ", the cabinet rear wall to socket center/fluorescent tube center distance for the second sign 20', and "d.sub.2 ", the socket center/fluorescent tube center to diffuser panel 38 distance, that is approximately equal in both signs 20, 20'.
The distance (d.sub.1, d.sub.1 ') between the cabinet rear wall 25 and the socket center/fluorescent tube center is determined by the distance needed to separate the fluorescent tube 30 from the cabinet rear wall 25. This distance (d.sub.1, d.sub.1 ') is based on socket dimensions and safety concerns. The distance (d.sub.1 ') may be, and typically is, different for both signs 20, 20', due to the different socket arrangements. This distance (d.sub.1 ') is typically greater in the second sign 20', as compared to the corresponding distance (d.sub.1) in the first sign 20, due to the tombstone sockets 44 (FIGS. 3, 4b and 4c), that account for the increase in cabinet rear wall to socket center/fluorescent tube center distance (d.sub.1 ').
In the first sign 20, for example, the distance (d.sub.1) may be approximately 1.1875 inches (3.02 cm) or greater. In the second sign 20', for example, a typical cabinet rear wall to socket center/fluorescent tube center distance (d.sub.1 ') includes the distance in the tombstone socket, designated as "r", the distance from the socket center (socket center/fluorescent tube center when a fluorescent tube 30 is in the socket 44) to the wireway 45 (or the edge of the tombstone socket 44 contacting the surface of the wireway 45, that are approximately equal), plus wireway thickness to the cabinet rear wall 25. This distance, "r" typically measures approximately 1.25 inches (3.18 cm), while the wireway typically is of a thickness of approximately 0.4375 inches (1.11 cm), combining for an exemplary distance "d.sub.1 '" of approximately 1.6875 inches (4.29 cm).
The distance between the socket center/fluorescent tube center and the diffuser panel (d.sub.2) is in accordance with industry standards. It is the distance between the socket center/fluorescent tube center and the diffuser panel 38, where the light diffuses uniformly throughout the cabinet 22, such that: 1) the viewer sees the graphic illuminated at a uniform intensity distribution, as opposed to areas of greater intensity, known as "hot spots" and lesser intensity, known as "shadows"; and 2) the viewer has difficulty in determining the direction of the lights 30 in the cabinet 22. Typically, this distance (d.sub.2) is approximately 4 inches.
The combined distances, the sum of which is the respective internal cabinet depths, d and d', for the respective signs 20, 20', results in overall cabinet depths D, D', for the respective signs 20, 20', of greater than four inches. This is due largely in part to the distance (d.sub.2), typically being approximately 4 inches. The internal cabinet depth d' and resulting overall cabinet depth (D') for the second sign 20' is slightly greater than those corresponding depths associated with the first sign 20, due to the tombstone sockets 44, as explained above (and the desire to keep the fluorescent tubes 30 level between the sockets 42a, 42b and 44, so as to avoid risking damage to the fluorescent tubes 30).
When these signs 20, 20', are mounted on walls 21 or the like, they extend (protrude) at least greater than four inches therefrom. By extending approximately greater than four inches from the wall 21, these conventional signs 20, 20' are commonly referred to and classified as "high profile."
These conventional "high profile" signs exhibit substantial drawbacks. Their "high profile" cabinets do not conform with the Americans With Disabilities Act Of 1990 (ADA), and in particular the ADA, at 36 CFR XI (Jul. 1, 1996 Edition), Pt. 1191, App. A, Section 4.4.1. This section requires that "Objects projecting from walls with their leading edges between 27 and 80 in (685 mm and 2030 mm) above the finished floor shall protrude no more than 4 in (100 mm) [(100 mm as converted by the ADA)] into walks, halls, corridors, passageways, or aisles."
The technology associated with the conventional signs 20, 20' and the like, is not suitable with "low profile" signs, as "low profile" signs extend not greater than approximately four inches from walls. This is because simply decreasing the distance between the socket center/light center and the diffuser panel (d.sub.2), does not allow for the uniform diffusion necessary for proper aesthetics. Rather, the diffusion and subsequent light distribution in the cabinets would be uneven, resulting in unaesthetic hot spots and shadows. Moreover, the viewer could easily visibly distinguish the direction of the fluorescent tubes in the cabinet.
To conform with the ADA, these conventional "high profile" signs 20, 20', with cabinets of greater than four inches in depth, must be placed into the walls, by cutting the walls and setting the cabinets back into them. This retrofitting is expensive and destructive to the walls, and should the wall be a structural or load bearing wall, this retrofitting is not possible.